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Size Distribution of Particles from Inhalers - Influence of Inspiratory Flow Rate and Humidity.
Ondráčková, Lucie ; Ondráček, Jakub ; Kozáková, Jana ; Ždímal, Vladimír
The purpose of this research was to determine the influence of inspiratory flow rate and relative humidity on particle size distributions (PSDs) generated by three MDI inhalers (Flutiform, Fullhale and Ventolin) and one DPI inhaler (Spiriva). Particle size distributions were measured by APS 3321 (TSI, USA) for three different inspiratory flow rates – 30, 60 and 90 l/min. Hygroscopicity of particles was determined by comparing data obtained at laboratory conditions and at relative humidity of 90%. During the measurements of number PSDs by using of APS spectrometer, we recorded bimodal distributions for Flutiform and Fullhale and monomodal distributions for Ventolin and DPI Spiriva. The increasing inspiratory flow rate had a negligible effect on the position of modes of individual distributions. The differences in PSD, measured under ambient conditions and at RH of 90%, were also minimal and did not significantly affect the assumed probability of drug deposition.
Fulltext: content.csg -  PDF
Plný tet: SKMBT_C22018110212481 - PDF
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A detailed study on aerosol particle size distribution in indoor and outdoor environments with attention to ammonium nitrate transormations
Talbot, Nicholas Philip ; Ždímal, Vladimír (advisor) ; Hovorka, Jan (referee) ; Vojtíšek, Michal (referee)
Due to its prevalence over large, densely populated areas, ammonium nitrate is an important chemical species in aerosol research. However, due to its volatility at ambient temperatures and over low temperature gradients, ammonium nitrate can be a difficult species to accurately measure. The volatility of ammonium nitrate is known to be dependent on temperature, relative humidity, the internal mixing state of the particle, and availability of the precursor gas constituents. The particle's physical state affects the equilibrium constant value of the ammonium nitrate - nitric acid / ammonia exchange and helps determine the dissociation rate. For indoor aerosol research, the outdoor originating aerosol particles' exposure to the new physical conditions indoors, such as changes in temperature, humidity, and particle-surface reactions within the microenvironment all accelerate ammonium nitrate dissociation. This increased rate of partitioning can generate artifacts on datasets, increase indoor particle formation, and accelerate the corrosion of cultural antiquities through acidification. The magnitude of these impacts is uncertain due to the current lack of knowledge on particle transformation processes when outdoor originating particles migrate indoors. To address this gap in knowledge, this thesis...
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Model for a Fluid-Particle Breakup in a Turbulent Flow.
Zedníková, Mária ; Vejražka, Jiří ; Stanovský, Petr
A model is developed for predicting the outcome of breakup of a fluid particle (bubble or drop), which is initially deformed (e.g. due to turbulence) and breaks into two daughter particles. An initially dumbbell-shaped deformation of the particle is assumed. The evolution of sizes of particle sub-parts is calculated using Rayleigh-Plesset equations, which consider the inertia of surrounding fluid, capillary action and viscous effects. The redistribution of internal fluid in the particle is calculated using Bernoulli equation. The model computes the sizes of daughter particles after the breakup. By assuming various initial conditions (various initial shapes and initial velocities of deformation), the size distribution of daughter particles is obtained. These size distributions are qualitatively compared with available experimental data and reasonable agreement is observed. Because of strong assumptions, this model cannot be used directly for accurate prediction of size distribution after a breakup. However, it provides an insight in the physics of the breakup, especially on the effect of inner phase properties.
Fulltext: content.csg - PDF
Plný tet: SKMBT_C22017030713510 - PDF
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The Influence of Fines on Pore System of Concrete
Elfmarková, Veronika ; Smolka, Hynek (referee) ; Hela, Rudolf (advisor)
Literature does not provide a satisfactory answer to maximum and minimum particle size or the particle size of the mortar phase especially for optimal porosity of concrete. To overcome the shortcomings of the design methods were thought to design a new method for design of concrete mix. This idea is based on a complex analysis of powder materials (determination of granular properties, shape factor of fillers, porosity, packing of powder materials, surface area, etc.) and subsequently to assess the influence to pore system of concrete and physical and mechanical properties in hardened state of concrete. In this work are presented and analyzed two types of fillers – fly ash and limestone dust.
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Bulk properties of fine particulate solids as the function of the selected material parameters.
Slanina, Ondřej ; Roman,, Fekete (referee) ; Svěrák, Tomáš (advisor)
The theoretical part of the thesis focuses on the description of particulate materials and their mechanical behaviors with a focus on flow properties. Great emphasis is placed on measuring the shear properties using a Jenike shear machine, on the correct procedure for standardized measurement and evaluation using Mohr's circles. The theoretical part focuses on the characterization of particulate matter using a variety of methods available, such as visual, separation, sedimentation, surface methods and methods of scanning field and flow. The practical part is focused on the determination of flow characteristics and surface finishing of finely ground limestone Omyacarb VA with various grain sizes. The surface was modified using stearic acid and calcium stearate. Attention was paid to the influence of the concentration of surface-regulating substances on the flowability of the material. The flowability of commercially supplied material was compared with lab modified materials and the determination of the theoretical content of stearic acid or calcium stearate was accomplished. Shear properties were measured using the Jenike shear machine. The material was further tested by laser diffraction and SEM with EDS particle surface analysis and elemental surface mapping.
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The study of polymorphism and optimization of active pharmaceutical ingredients crystallisation
Novák, David ; Ing.Ladislav Cvak, Ph.D. (referee) ; Ing.Roman Gabriel (advisor)
Active pharmaceutical ingredients (APIs) are frequently delivered to the patient in the solid-state as part of an approved dosage form (tablets, capsules, etc.). Understanding and controlling the solid-state chemistry of APIs is therefore an important aspect of the drug development process. APIs can exist in a variety of distinct solid forms, including polymorphs, solvates, hydrates, co-crystals and amorphous solids. Each form displays unique physicochemical properties that can profoundly influence the bioavailability, manufacturability, stability and other performance characteristics of the drug. Most APIs are purified and isolated by crystallisation from an appropriate solvent during the final step in synthetic process. The main objective of a crystallisation process is to produce crystals with desired properties such as particle size distribution (PSD), shape and purity. All pharmaceutical dosage forms must be produced in uniform units, and good content of uniformity is only possible when the size of the active component is carefully controlled. For on-line control of crystallisations of Quetiapine Fumarate to achieve desired PSD and no changed physicochemical purity was used the Lasentec Focus Beam Reflectance Measurement (FBRM) system.
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Robust Approach for Environmental and Health Practice: Novel Paradigm for Data Treatment and Analysis
Wagner, Zdeněk ; Ocelka, T. ; Pavliska, L.
Knowledge of concentration of atmospheric aerosol particles may provide an important information in applications concerning human health. Aerosol studies reach into several fields of science. In the past decades it was shown that enhanced concentration of atmospheric aerosol lead to increased mortality on cardiopulmonary diseases and lung cancer. This work presents a robust method of estimation of particle size distribution based on mathematical gnostics. The algorithm may either be used as a manual tool for analyzing a small number of particle size distributions ex post or as a routine implemented in automatic monitoring devices for near real time processing of measured data and immediate online display on a web site. The method has sucessfully been implemented for near real time analysis of data measured by a scanning mobility particle sizer conformant to recommendations defined in the framework of the EUSAAR project.
Fulltext: content.csg - PDF
Plný tet: SKMBT_C22013071913360 - PDF
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Porovnání ultrajemných atmosférických aerosolů v Praze a Budapešti
Matějková, Daniela ; Borsós, T. ; Ždímal, Vladimír ; Salma, I. ; Schwarz, Jaroslav ; Smolík, Jiří
Data measured in Prague suburbs and Budapest city center have been compared in the time period from November 1, 2008 until August 31, 2009 in the size range from 10 nm to 1 µm. Total average particle number concentrations were calculated, 6.8×103 particles/cm3 in Prague, and 1.3×104 particles/cm3 in Budapest. The size distributions were mostly bimodal with the mode located either in the Aitken (25–100 nm) or in the accumulation mode range (> 100 nm). When new particle formation started in the atmosphere, the nucleation mode (< 25 nm) appeared growing from the lowest detectable sizes upwards.
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